Method of manufacturing commercial products from phosphatic material



May 5, 1931. J. w. wALToN METHOD OF MANUFACTURING COMMERCIAL PRODUCTS FROM PHOSPHATIC MATERIAL Filed March 23, 1929 3 Sheets-Sheet l @vwo/nim www MMMVM May 5, 1931. J. w. WALTON A1,803,417'

' METHOD OF MANUFACTURING COMMERCIAL PRODUCTS FROM PHOSPHATIC MATERIAL Filed March 23. 192'9 5 Sheets-Sheet 2 May 5, 1931.

ETHOD OF MAN Patented lMay 5, 1931 UNITED STATES PATENT o'FFlcE H11' WILLIAM WALTON, OF ROCKDALE, TENNESSEE, ASSIG-NOR, T0 TENNESSEE PRODUCTS CORPORATION,' 0F NASHVILLE, TENNESSEE, A CORPORATION OF TEN- NESSEE METHOD OF MANU FAGTURING COMMERCIAL PRODUCTS FROM PEOSPHATIC MATERIAL Application led March 23, 1929. Serial No. 349,328.

rlhis invention relates to the method of manufacturing commercial products from phosphatic material, such as phosphatic ores, through the treatment thereof in a blast furnace.l

More particularly stated, the invention relates to a method of treating phosphatic ore, rock, or the like, along with carbon, iron bearing material, and a suitable flux, in a furnace of the blast furnace type and recovering therefrom of various useful commercial products, such as ferro-phosphorus, slag, phosphorous bearing gases, and the like, from which other ycommercial products may be derived. A

rlhe object of the invention is to subject phosphatic ore or other phosporous bearing material, along with carbon, iron bearing material, and a suitable flux, to treatment in a blast furnace, and to recover from the products of such treatment various useful commercial substances and materials, or substances and materials from which useful commercial products may be derived.

A further object is to produce, in ablast furnace, compounds of phosphorus and iron, including the product known as ferro-phosphorus, more economically and efficiently, and

of better grade or qualitythan has been possible heretofore.

A further object is the production of phosphids of iron in a blast furnace and-to obtain as commercial products various substances and materials such, for example," as elemental phosphorus, phosphoric anhydrid,

phosphoric acid, slag, mineral crore, wool,`

and various other products, and of various characters and forms, including polishing powders,- fertilizers, and other commercial products, from the furnace gases evolved in `the operations of producing the said phosvphids of iron, as well as from the slag produced, t o A furthery object is to improve the methods heretofore generally employed in the manufacture of phosphids of iron, to improve the character and quality ofthe phosphid of iron products, to eliminate or reduce various op.

erating difficulties heretofore encountered in the operation of blast furnaces in the production of ferro-phosphorus, or other form of phosphid of iron, such as clogging up of the furnace, the formation of bridges or scaffolds, and various other difficulties heretofore encountered which have seriously interfered with'the operations of the furnace, and to secure economy and eiiciency in the operation of the furnace.

Other objects'of the invention will appear more fully hereinafter.

The invenion consists substantially in the modes of operatiom'all as will .be more fully hereinafterset forth in connection with the accompanying drawing, and finally pointed out in the appended claims.

u Referring to the accompanying vdraw- 1ngs- Figure 1 is a view,v somewhat diagrammatic, illustrating a furnace of the blast furnace type, and a portion of the apparatus employed in treating the by-prducts obtained from the operation of the furnace;

Fig. 2 is a diagrammatic view illustrating a In the operation of -blast furnaces in the',l manufacture of phosphidsv of iron, such, for' example, as the product known as ferro-phosphorus, as heretofore ordinarily carried out, the phosphatic ore, rock or the like, iron bearing material, carbon, and a suitable flux, are charged into thetop of the furnace, and heat is generated by igniting the stack or pile of V material so charged at the base thereof, and .supplying a blast of air to maintain combustion thereof. The gases and other heated products ofl the combustion rising through the stack or pile of material reduces the iron material to the metallic state as such material descends through thefurnace, and v,also liberates phosphorous gases from the phosphorous bearing materials. In the lower region of the furnace the phosphorous gases react with the liberated iron, the iux material serving as a catalyst to effect such reaction, in the presence of the carbon and of the heat generated, the operation resulting in the production of phosphids of iron, including ferro-phosphorus, slag, phosphorous bearing gases, and other compounds containing phosphorus.

I-Ieretofore in the operation of blast furnaces for the production of ferro-phosphorus very great operating diculties have been encountered, such as the clogging up of the furnace, the formation of bridges, or of scaffolds within the furnace, and various other difficulties, which seriously interfere with the operation of the furnace, which result in the production of too low a grade of ferro-phosphorus product, and which add very substantially to the cost of the operation. Moreover, while the slag produced, as well as the gases evolved during the operation of the furnace for ferro-phosphorus production have been known to contain valuable properties, and especially valuable quantities of phosphorus 'in various forms of compounds, no serious effort has heretofore been directed to recovering and utilizing such properties and substances in the form of commercial products. Instead, such slag and gases, for the most part, have been regarded as waste products, and the values thereof have consequently been lost.

Again, it has not been realized heretofore, so far as I am aware, that a proper regulation and control of the production of the waste slag and phosphorous containing gases, during the operation of the furnace, and the elimination or removal of the gases at the proper points and stages of their formation and evolution, not only results in the production of a better quality and 4grade o ferrophosphorus product, by securinga more energetic and complete reaction of the iron and phosphorus, but also in achieving a more rapid, efficient and economical operation of the furnace, while at the same time securing a slag product, as well as phosphorous bearing compounds and gases, of such a nature and character as to enable them to be eiciently treated to produce various desirable commercial products.

My present invention relates more particularly to the control and regulation of the slag product, as well as that of the phosphorous gases and compounds evolved during the reduction of ferro-phosphorus in a blast urnace, and the withdrawal of the said gases from the furnace at the proper times, and from the proper points whereby to produce more efliciently and economically a better quality and grade of ferro-phosphorus product, while at the same time securing a slag product, as well as phosphorous gases and compounds of a suitable nature and character and the treatment thereof in the production of various commercial products, such as mineral or slag wool, elemental phosphorus, phosphoric acid, cleaning or polishing powder, fertilizers, and other products.

I have discovered that in the treatment of phosphatic containing ores or material in the operation of a blast furnace, distinctively different characters and qualities of gases may be obtained, according to the location of the point in the furnace from which such gases are drawn ofi'. Thus, the gases taken or drawn off from the top of the furnace, particularly where the amount of phosphatic ore or rock employed is relatively small, gen-` erally carry only a small quantity of phosphorus or phosphorous compounds, and are generally accompanied by a large amount of impurities derived from the materials which are charged into the furnace. l

It is my belief that the impurities contained in these gases taken off from the top of the furnace, and which, in large part, are carried mechanically by the gases, are produced by the attrition exerted by such gases during the rapid speed of flow thereof upon the particles of the charge. I base this belief upon the fact that the impurities are usually carried along with the gases in a finely divided state. The gases drawn from the top of the furnace are ordinarily utilized in various of the accessory appliances of the furnace, such as in the hot blast stoves to preheat the air blast supplied to the furnace, in heating the boilers of the power equipment, etc. The presence of the impurities in these gases very seriously interferes with the economical and eicient operation of the furnace plant as a whole, by clogging up or obstructing the passages through which such gases travel. This interference with and impairment of the operation as a whole naturally has its injurious effects upon the ferro-phosphorus as well as upon the slag and phosphorous bearing gases and compounds produced in the operation of the furnace.

On the other hand, I have discovered that the gases produced and existing in the lower and hotter portion of the furnace, when withdrawn from the region in which they are produced, and where they exist, are not only com aratively free from impurities in a inely divided state mechanically carried along with such gases, but the are also richer in phosphorus, as Well as 1n phosphorus pentoxid (P205), as compared with the gases drawn 0E from the top of the furnace. It is my belief that the reason for this dierence in the nature and character of the gases drawn from the two different points of the furnace, referred to, is that in a blast furnace in which iron bearing ore or material and phosphatic ore or rock are fused or melted together, two melting zones are produced. The phosphatic ore or rock requires a much higher fusing temperature than iron, limestone, silica, etc., and consequently the gases drawn from the top ofthe furnace are mainly generated by Vthe fusion of the iron ore, limestone, silica, etc., and ,hence are necessarily leaner in phosphorus, whereas those drawn from the hotter portion of the furnace are produced as a result of a more complete fusing of the phosphatic ore or rock, and consequently are richer in phosphorus Another explanation of the difference in character and nature of the gases from the two points of the furnace,

referred to, according to my belief. and'experience, is that the reduction of the phosphatic material is facilitated by bringing that material into ,contact with incandescent carbon. Iron oxid, on the other hand, is readily reduced I by carbon' monoxid gas. The heatedgases ascending through the shaft of the furnace, therefore, appear to effect the reduction ofthe iron ore, at least to a considerable extent, at a considerable distancel above the region of the tuyres where the air blast is supplied into the furnace,

.whereas the phosphatic material, asl well as the carbon, attains its incandescent state in the region .of the tuyres, and in that state the phosphatic material is more readily reduced by the incandescent carbon. Consequently the gases generated and existing in the furnace at the hottest point, namely, in

the region of the tuyres, are much richer in phosphor content, than are those drawn from the top of the furnace. n

The' rapid speed of travel of the gases through the body of the charge in the furnace, in the case of the gases drawn .off from the top of the furnace, andas above stated, causes such gases to carry along with them fine particles of material rubbed from the ore, carbon, etc. of the mass contained in the furnace shaft. This is not so much the' case with the gases drawn from the region of the hottestiportion of the furnace, and consequently the last mentioned gases arefreer from such mechanicallycarried impurities.

In accordance with my invention, therefore, I propose to independently draw off gases from the top of the furnace, and fromI 4the baseor region of the hottestpart of the furnace, and to separately treat such gases, as will be more fully hereinafter set forth, so as to take'full advantage of the different natures and characters of such gases, in the utilization in commercial products of the valuable constituents thereof.

T have found that by drawing off gases from the base or hottest portion of the furnace, with or without drawing also from the top, conditions are "created 1n the furnace which result in a more rapid perfect and complete fusion of the charges. This results in producing an improved and better quality of ferro-phosphorus product in a shorter space of time, as well as a more readily-fusible slag product. A slag product which is easily and readily'fusible is desirable where such prodtakenv into uct is to be utilized in the production of a mineral or slag wool product, as will be hereinafter described. The enhanced quality of theV ferro-phosphorus product, and the increased fusibility of the slag product, secured by drawing olf the gases in the manner and from the points above mentioned, I believe to be due, largely, to the fact that a better and more perfect fusion of the materials charged into the furnace is. secured,`and a more-perfect reaction takes place. I base this belief upon the fact that by withdrawing more or less of the gases, particularly those evolved and existing in the region of the tuyres, and the same holds more or less true also as to the gases drawn olf from the top of the furnace, opportunity'is per- -preventing the presence and maintenance of suflicient free carbon in the fusion zone in the region of the tuyres to accomplish the reaction, with the flux, of the elemental iron and phosphorus to produce the ferro-phosphorus product. This secures greater economy, as well as a higher grade and quality of ferrophosphorus product. It secures a more desirablev slag product for subsequent utilization, and it enables the utilization of the two characters and qualities of gases drawn off respectively from the top and bottom portions of the furnace shaft in the production of commercial products according to the respective characters and qualities thereof.

ln the operation ofthe furnace, in carrying out my invention various factors must be consideration. The burden charged into the furnacemust be properly balanced and maintained in that proper balance. Should an unbalanced condition of burden occur, the ordinary furnace man, by

well known methods, can readily ascertain in checked by suitable and proper chemical analyses according to well understood and well known methods. I have found that atmospheric conditions and humidity affect the fusion conditions in the furnace and hence, also, the character of the ferro-phosphorus and slag products, as well as the gases, especially when working with phosphatic ores. Therefore, in carrying out my invention the working and performance of the furnace must be carefully watched and controlled accordingly, not only in connection with the proper balancing of the burden but also with respect to the supply of air blast, its dryness, quantity and heat. I have found in practice that a supply ranging from four thousand to sixteen' thousand cubic feet of air per minute, according to the nature, character and conditions of the burden, the atmospheric conditions of heat and humidity, and the size of the furnace, is satisfactory to main tain the two melting or fusion points or zones at their proper respective locations in the furnace tend to secure the efiieient fusion and reactions of the materials employed. If insuflicient air is supplied to the furnace, the phosphatic and iron bearing materials are not properly fused, and do not properly react or combine, resulting in an inferior grade and quality of ferro-phosphorus and an insoluble slag product unsuitable for use in the manufacture of the same into a wool product. If too great a volume of air is supplied, the melting or fusion points will be raised to too great a height in the furnace. rPhat would result in setting free the phosphorus pentoxid (P205) at a point too high up in the furnace to properly combine with the iron with the result, likewise, of producing an inferior grade of ferro-phosphorus, as well as an undesirable insoluble slag. However, with a proper balance of burden, proper control of the operations of the furnace, and of the air supply a complete Vand effective fusing and combining reaction of the materials is attained, a ferrophosphorus product of improved and en haneed quality and grade is secured, and a slag product is obtained which contains a large percentage of soluble silicates and which is soluble in hydrochloric acid. W'hen the slag possesses these characteristics it is suitable for use in the production of a wool product which is useful as an insulating agent for heat, cold, or for electric currents.

An illustrative burden of proper balance, depending on the various conditions referred to, I have found to be as follows:

5200 pounds of coke (84% carbon) 4400 pounds phosphate rock (containing from 12% to, say, 17% phosphorus) 3200 pounds iron' ore (containing from 38% to 50% iron) 2400 pounds iron ore tailings (containing from 40% to 60% or 70% silica, and 10% to 30% iron) An air blast of from eight thousand to twelve thousand cubic feet per minute.

It is to be understood, however, that this is only an illustrative burden which I have found, under certain conditions, to be satisfactory. My invention, therefore, is not to be limited or restricted to the exact proportions give, as such proportions may be varied from throughout a wide range and still the benefits and advantages of my invention realized in whole or in part.

Itis also to be understood that a soluble slag suitable for producing an insulating wool may be obtained from other materials and substances, besides those named in the illustrative burden above given, and still fall within the scope of my invention.

In the accompanying drawing I have shown a conventional form of lblast furnace to illustrate the manner of carrying out my invention. Generally, the furnace consists of a. vertical shaft portion A, into the open top of which the material to be treated is charged, the open top being closed, after the charge is introduced by a bell or other closure B. The shaft portion A tapers interiorly from its lower towards its upper end. Below the lower end of the shaft portion A is the portion C, usually of decreasing area downwardly from its line of junction with the shaft portion A. Within this portion C the principal reaction of the melted iron and elemental phosphorus takes place. Near the bottom of the portion C are located the tuyres D through which air blasts are delivered into the furnace.

Below the tuyeres are the chamber portions Il, I", in which collect the ferro-phosphorus, or other metallic phosphid, and the slag, respectively. and from which said products may be drawn or tapped off through the notches G, Il. Communicating witi the shaft A, at or near its upper end, is a downcomer pipe Ii through which gases may be drawn from the upper end of the furnace. Communicating with the portion C of the furnace at a point in the vicinity of the tuyeres are one or more gas outlets or eX- tractors .I through which the gases generated and existing in the region of the hottest part of the furnace may be drawn off. The particular location of these outlets or extraetors is not of consequence so long as they are so located as to serve the purpose of drawing olf or extracting the gases from the region of the reaction chamber, where the greatest heat and pressure are developed, that is, from the region where the iron and phosphorus combine and react to produce ferrophosphorus.

The `material employed, in the form of carbon, phosphatic material, iron bearing and iiuxing material, as silica, are charged into the furnace in the manner now well known and practiced. This mass is ignited ing ore or material being gradually reduced to the state of metallic iron, and the phosphatic material being reduced to the state of phosphatic gases and elemental phosphorus.'

The melted iron and the phosphorus then Y combine or react in the presence of the linxing agent and a high degree of heat, as well known in the art, to form the ferro-phosphorus product. This reaction takes place mainly in the portion C of the furnace, and the necessary high degree of heat is secured by the air blasts acting upon the ignited carbon, there being a. maintained sufiicient l amount of free carbon in this zone of the apparatus to supply the heat requirements of the reaction which reaction is endothermic in character.

This, generally, is a typical form of blast furnace and a typical mode of operation thereof, and by the employment of the gas extracting connections J, K, I am enabled to carry out my invention, as hereinabove explained. I will now describe the treatment of the slag produced in the manner, and by the operations hereinabove described, for the purpose of making a commercial wool product. f

As above explained, by my invention a slag product which contains a large percentage of soluble silicates, and which is soluble in hydrochloric acid, is produced, which collects in the portion F at the base of the furnace. This sla-g is drawn oli' in molten condition through the notch H and delivered into a ladle L. From this ladle, or otherwise, the molten slag is caused to pour in a thin stream, see Fig. 3, which stream is intersected by a jet of steam or air, as indicated at 10, which blows the slag into wool form.

I have found it desirable to carry on the jet operation in such man er as topermit the resulting wool to be esbosed to the atmospheric air. This may be accomplished in various ways. One simpleexpedient is to 4carry on the jetvoperations within a large wire cage or chute, indicated at 11. yIn this manner' the free access of air to the shredded or wool product, while being shredded or reduced to wool form, is afforded.

it to proper shape and form for yuse for various purposes. l`For illustration. vI have .shown. a storage-bin M into which the wool product is blown, and from which, by suction, or in any other convenient manner, the

' product may be drawn .for such treatment.

I have found it convenient and desirable in forming the wool product into suitable commercial shape to employ. a binder material therefor. For this purpose I have used with success silicate of soda 42 Baum. My invention, however, is not to be limited, or restricted in its broadest scope to this specific binder material, or to the use of any binder.

yWhere a binder material is used the wool product is first roughly shaped into the form of the desired commercial roduct. This can be conveniently accomplished by packing the wool into a tray or mold, indicated at 12. The roughly shaped product is then dipped into the binder solution, for instance, into a dilute solution of silicate of soda, as indicated at 13, and then subjected to pressure, as indicated at 14, to remove any excess of the binder solution. The product is then dried and is ready for sale and use. For conbeing pressed yis placed for transportation into a shed or storage house 16.

In forming up the wool material into com'- mercial shape, and particularly for convenience in handling such wool product during the operations of applyinfr the binder solution thereto, of pressing, (T the roducts, and particularly where such pro uct is formed into slabs, plates or panels, I have found it desirable to employ trays, molds, see Figs. 4, 5, 6, having perforations or slits indicated at 17, in the bottoms thereof, and having perforated side and end members 18,' hinged to the bottom plate and held in box formation by means of pivoted hasps 19. This structure of mold, however, while convenient is not necessar and any `other device for and method of orming the wool material into the desired shape may be adapted and used.

Where a tray or mold is used, whatever its structure, `the wool material is placed therein in the desired amount or if no mold is used the wool material, 1n the desired amount is' fashioned into the desired shape by hand or otherwise, and a sheet or covering 20, see Fig. 5, of suitable material is placed thereover. Various covering materials may be used for the purpose. I have found a fibrous sheet, such as a sheet of craft paper well answers the purpose. Over this Ifibrous sheet or covering I sometimes place. a sheet 21 of ordinary wire nettingfor hardware y cloth, preferably of comparativelyiine-mesh. The shredded or wool product is collected Th and stored for further treatment to reduce e purpose of the fibrous sheet for covering, and of the sheet of wire netting v-is tov prevent the adhesion of the molded-article toany` surface onl which itimay be placedwhilebeing dried or seasoned, while at thesame time -per-y mitting access of air to the'body. of the molded article to facilitate the drying and seasoning thereof. If desired', and while the article rying and storing `215 hydrid (P205) as compared with is being subjected to the action of a press, after havin been treated to the binding solution, a sieet of iron may be placed over the molded article. After the article has been pressed, it, together with the fabric sheet and sheet of wire netting, is removed to the drying and seasoning room, as above pointed out.

I have found that the wool product ob- 10 tained from the slag residue of ferro-phosphorus as described, when produced under the conditions of control and operation as hereinabove explained, contains a large percentage of silica, say from 37% to 50%, the slag product being soluble in hydrochloric acid, and when formed into slabs, sheets, panels or other form it makes an excellent heat as well as electric current insulating material.

I Will now describe more in detail the utilization of the gases drawn from the portion C of the furnace.

As hereinabove stated, these gases are r'ich in phosphorus as well as in phosphoric anthe gases taken from the top of the furnace, due to the more perfect fusing and combining reactions which take place, in carrying out Iny invention, within this portion of the furnace. 80 rIlhese gases, may be treated in various ways to recover therefrom their valuable phosphorous contents. It will be understood that the gases within the furnace in the region of the tuyres, say in a region roughly determined by the level of the slag upwardly to the top of the bosh, or widest part of thefurnace, are subjected to the maximum temperature developed in the furnace. This teinperature may run, for example, from 2000o F. to 3000 F. These gases, within the region referred to, are maintained under a pressure of from four pounds to, say, fifteen pounds above atmospheric pressure. This temperature and pressure, of course, to which the gases are subjected in this portion of the furnace, will vary according to the practical conditions under which theY furnace is operated and, accordingly, the best location of the point in the furnace from which the said gases are withdrawn, can ordinarily be found by practical experience in operating the furnace. I havel found that a location of the point of withdrawal at an elevation of around eighteen inches above the tuyres gives satisfactory results, but obviously my invention is not to be limited or restricted in this respect.

One practical method of drawing off the gases from the region of the tuyres, as I have defined that region, which I have found etlicient and suitable, is to insert one or more pipes J through the wall of the furnace, said pipes opening at their inner ends into the furnace, and to connect the outer ends of such pipes to an enlarged drum or mufer N. The gases are forced from the interior of the furnace by the pressure under which they are subjected, through this pipe connection J, into the muffler N. I prefer to deliver into the pipe connection J a jet or spray of water or steam. This can be accomplished in various ways. A simple arrangement is to locate a spray jet or head'within the pipe connection J and to deliver thereto water or steam under pressure, as, for example, through pipe connection 25, from any convenient source. lVhere Water issupplied it is instantly converted into steam which becomes superheated from the heat of the gases. The purpose of supplying the Water, or steam, into the pipe connection J, is twofold. In the first place it prevents the pipe connection J from burning out under the high temperature of the gases, and in the second place, and, more important, the superlieated steam reacts upon the gases in such manner as to cause a deposit of substances upon the inner wall surface of the pipe connection. This deposit adheres to the surface of the pipe and forms a coating or lining constituting a heat insulation there-y for. I have found this coating substance to be composed principally of silica having in admixture therewith varying amounts of elemental phosphorus, red phosphorus, and possibly other phosphorous compounds. Just what chemical reactions take place within the pipe connection J, and within the drum N, I am unable to say with accuracy, but it is my belief that when the hot gases come in contact with the water which has been converted into superheated steam, ammonia, phosphin, and other compounds are immediately formed. In the case of ammonia the nitrogen element thereof obviouslyl is obtained from the air of the air blast supplied through the tuyres. I have demonstrated that ammonia gas is copiously produced, and this indicates to me that the gases arel maintained in the furnace under pressure. I have found in practice that after the deposited lining has been formed, as above explained, on the inner surface of the pipe, the water (or steam) jet may be cut off. In such case, however, care must be taken to prevent the continuation of the deposit to the point where it will clog the entire bore of the pipe connection J. I find that this danger of clogging from a deposit of a coating or lining extends also to the drum N, as well as to the pipe connection 26 delivering from the drum, and consequently care must also be taken to prevent such clogging of the drum and delivery pipe therefrom.

I have found that an accumulation of fluid, sludge, etc. takes place within the drum N, which should be drained off from time to time. For this purpose a valve controlled drain pipe 27, see Fig. 1, may be connected to the bottom of the drum N and to a sludge pipe 28. This Huid or sludge, I have found,

contains quantities of various substances,

namely, elemental phosphorus, red phosphorus, silica, aluminum, and other compounds which may be recovered by sedimentation or otherwise.

For this purpose I have shown the sludge 28, Fig. l, delivering through valve controlled connections 29Yto one or more settling tanks 30, see Fig. 2. Any supernatant water collecting in the settling tanks 30, may, if desired, e pumped back into the water system and used over again in the water jet. I have shown a pump 31, Fig. 2, for this purpose which delivers the water from the settling tanks 30 through pipe 32 to the Water Jet pipe at the fitting J. As this water carrles with it more or less phosphor content byusing such water over and over again the phosphor content is permitted repeated opportunities to eventually settle out and to be recovered.

The substances which accumulate as sediment in the settling tanks 30, may be collected and treated in any suitable or appropriate way to recover the phosphorus and other valuable contents thereof. I have found a simple and efficient way to treat this sediment is to distill the same and recover elemental phosphorus from the distillate. This product is then molded into convenient form for sale and commercial use. I have indicated a simple arrangement for carryingout the operation referred to wherein the sludge or sediment which collects in the settling tanks 30, are `drawn off therefrom by means of a pump 33, and delivered into a storage tank 34. From this storage tank the material is delivered through a valve controlled pipe connection 35, into a still 36. This still may be of any suitable or desired type. A rotary drum type is shown.

The elemental phosphorus contained in the hot vapors given olf from the still may be collected and recovered therefrom in fmany different ways. In practice I prefer to deliver said hot vapors into a bodyof comparatively cold water to cause the phosphorus to congeal into a waX-like mass, and to remove such mass and subject the same to the softening action of Nwarm or hot water to enable the same to be mlded into the desired commercial form or shape.

I have illustrated an arrangement suitable for carrying out this operation, wherein the hot vapors from the still 36 are delivered from the still through pipe 37, and thence into bodies of cold water contained in condenser chambers 38. The water should be of a temperature of 40 F. to 60 F. The waz;- like mass of phosphorus which is formed in the condenser chambers by the congealing action of the cold Water, is removed or drawn off fromv the condenser chambers and delivered into a trough 39, adapted to vcontain hot water, whereby the phosphorus is sufficiently'melted to be supplied into molds 40 immersed in a chamber 41 containing warm or hot water, whereby molded into the desired shape and form. The temperature of the Warm or hot Water employed in this connection should be suflicicnt to soften the phosphorus and enable it to be molded or shaped into the desired form. I have found thata Water temperature of from 100o F. to 125 F. is satisfactoryfor this purpose.

The residue of the distilling operation, after the removal of the phosphor vapors, is still rich in phosphatic material and I have found that when ammonia or potash salts are addedto said residue, an excellent merchantable fertilizer product is obtained therefrom.

Having described the treatment of the sludge, fluid,`etc.vobtained from the drum N into which the gases withdrawn at J from the furnace are delivered, I Will now describe the treatment ofthe gases delivered from the drum N through the pipe 26. The pipe 26 leads into a chamber 42, see Fig. 2, and its delivery end is immersed beneath the surface of a body of water contained in said chamber. By this arrangement the gas splashes or bubbles up through the water and is thereby scrubbed or filtered, leaving in the water or chamber a sludge or sediment similar to but which contains even a larger quantity of phosphor content than the sludge obtained from drum N. This sludge or sediment may be drawn off from chamber 42 and treated in the same Way above described to recover elemental phosphorus and a fertilizer as commercial products. I have shown the chamber 42, connected by valve controlled pipe connection 43, with the sludge pipe 28, through which the sludge drawn from chamber 42 may be added to and treated along with that drawn from the drum N, as hereinbefore described.

After the scrubbing or filtering action to which the gases are subjected in chamber 42, said gases may be delivered on through one or more other Water sealed scrubbing or lil/tering chambers similar in all respects to chamber 42, in each succeeding one of which they are subjected to a similar scrubbing or filtering action resulting in the collection of a similar sludge or sediment which, 1n turn, may be treated in the sam'e manner as above described. I have shown one such additional scrubbing chamber 44, which has a valve controlled sludge delivery pipe connection 45, to the sludge drain pipe 28. The gases are delivered from chamber 42 into chamber 44 through pipe connection 46. The operation, as above stated, may be carried on through additional scrubbing chambers, to

the phosphorus is vno any desired extent. The final residual gases e from any carbon monoXid or other infiamm'able gas constituent thereof, and also to convert any remaining elemental phosphorus present therein into pentoXid of phos ihorus or to anhydrid of phosphoric acid 2O5). he removal of the carbon monoxid and other inflammable gases is desirable in order to remove the dangerof explosion when said gases are subjected to the action of aprecipitator, particularly-if the precipitator is of' the electric type, and the conversion of any elemental phosphorus into the pentoxid reduces the phosphatic compounds remaining in the gases to a condition Which is suitable for the precipitation therefrom of phosphoric acid.

To carryv out this treatment in one practical and eflicient mode, I propose to burn the' gases and then subject the products yof the combustion to precipitation. I have shown an arrangement suitable for carrying out lthese operations, wherein the pipe 47 from the last of the scrubbing chambers 44, delivers into a suitable combustion chamber P, in which said gases are burned, to remove carbon monoxid and other inflammable gases therefrom, and to reduce any elemental phosphorus to pentoxid of phosphorus. From the combustion chamber the resulting gaseous' product, after being cooled down to a suitable temperature of say 90o F. to 110"v F., is subjected to the action of a precipitator R. This may be accomplished in any desired commercial type of 'precipitator, such for eX a-mple as an electric precipitator of the Cottrell type, the resulting precipitate being drawn ofi from the precipitator as phosphoric acid.

It is obvious thatthe heat developed by the burning of the gases in the combustion chamber P may be utilized for any desired purpose.

I will now describe the treatment to which the gases drawn from the top of the furnace may be subjected for the recovery of valuable comfmercial products therefrom.

As hereinabove explained these gases are lean in phosphor content, but they carry along with them particles of dust and other character of fines of the burden employed. In accordance with my invention I have discovered that these fines, dust, or the like, contain silica, alumina, lime, potash, iron oxid, phosphorous pentoXid, and perhaps other mate rials, which, in combination, or admixture, constitute a valuable cleansing and polishing agent in the form of a powder Which is unctious, impalpable and free from crystalline particles. This powder can be separated out from the gases in various Ways. I have found it convenient and practical to first preliminarilycatch and seperate out from the gases drawn from the top of the furnace, the larger particles of dust, carbon andthe like, and

" then treat the gases which ,retain the finer particles by burning the same, usefully employing in any desired Way, the heat developed by the burning of the gases, and finallyprecipitating the dust, fines, etc., from the products of such combustion.

I have indicated in the drawings 1) an arrangement of apparatus suitable for carrying out my invention with respect to the recovery of the polishing powder from the gases drawn from the top of the furnace. As shown, the downcomer K delivers into a dust collecting chamber S and thence passes by pipe 50 into a Washer T, containing water through which the gas passes.

The larger particles carried along with the gases Will settle down in the chamber S, or will be caught in the Washer T. From the washer the gases are conducted to the boiler indicated at V, for use in generating steam, or to the stove IV for preheating the air blast supply to the furnace, or to both these accesseries, Where said gases are burned. It is my belief that in burning the said gases, only the carbon monoXid and possibly other infiamma ble gases contained therein are consumed, Whereas the dust, fines and the like carried by the gases are not consumed.

After burning the gases, as above described, the products of combustion are subjected to the action of a precipitator, indicated at O. This may be an electric precipitator of the Well known Cottrell type. The action of the precipitator is to throw down as a precipitate the polishing material heretofore referred to in the form of a light grayish to White powder. This powder product, when analyzed is found to contain the following:

Should the dust product after precipitation be found to contain solid matter in uncombined condition, such, for example, as carbon, lime or the like to any undesirable extent, such foreign and undesirable material may be readily separated yout and removed mechanically by sifting or otherwise handling the recovered dust product.

The final dust product may be collected and packaged in any suitable or convenient form for sale commercially. i

From the foregoing description it will be seen that I provide a method by which ferrophosporus is produced more eiiicientl and economically than heretofore, and of better quality or grade, and by operations which also result in the production of -a slag product which is capable of being utilized in the production of a valuable commercial product, and in the production of gases which, like-- wise, are capable of being so treated as to produce highly valuable commercial products of various kinds. l v

I-Iaving nowset forth. the objects and nature of my invention, and the manner .of carrying the same .intopractical use and operation, what I claim as new and useful and of my own invention, and desire to secure by Letters VPatent is 1. In the manufacture of 'ferro-phosphorus in a blast furnace, the process which consists in charging the furnace with a suitable -mixture of phosphatic material, iron bearing material, iuxing material, and carbon,`igniting in the presence of incandescent carbon con-` the charge at the base thereof, and supplying air into the combustion zone to raise and maintain a temperature in said zone sulicient,

tained therein, to reduce the phosphorus of said phosphatic lmaterial to the elemental state and enable it to combine with the iron,

in the presence' of the fluxing material, and

withdrawing a portion of the gases from said zone to increase the temperature and reducing and combining action in said combustion zone.

2. In the manufacture of ferro-phosphorus' in ablast furnace, the process which consistsl in charging the furnace with a suitable mixture of phosphatic material, iron bearing material, fluxing material, and, carbon, igniting vthe charge at the base thereof, and supplying air into the combustion zone, withdrawing a portion of the gases from thecombustion zone and increasing the supply of air to the combustion zone.

4C. In the manufacture of ferro-phosphorus in a blast furnace, the process which consists Y in charging the furnace with a suitable mixture of phosphatic material, iron bearing materiahuxing material, and carbon, igniting the charge at the base thereof, and supplying air into the combustion zone, and withdrawing a portion of the gases'fromthe combustion zone to accelerate the reducing and combining action taking place in the combustion zone.

5. In the manufacture of ferro-phosphorus in a blast furnace, the process which consists in charging the furnace with a suitable mixture of phosphatic material, iron bearing material, fluxing material, and carbon, ignitmg the charge at the base thereof, and supplying air into the combustion zone, and withdrawing a portionof the gases from the combustion zone to increase the phosphorous content of the resulting ferro-phosphorus.

6. In the manufacture of ferro-phosphorus in a blast furnace, the process which consists in charging'the furnace with a suitable mixture of phosphatic material, iron bearing material, fluxing material, and carbon, igniting the charge at the base thereof, and supplying air into the combustion zone, and withdrawing a portion of the gases from the combustion zone to control and regulate the grade and quality of the ferro-phosphorus, slag and gas products of the furnace.

7. In the manufacture of ferro-phosphorus in a blast furnace, the process which consists in charging the furnace with a suitable mixture 'of hosphatic material, iron bearing material, uxing material, and carbon, igniting the charge at the base thereof, and supplying air into the combustion zone, and controlling and regulating the resulting ferro-phosphorus, slag, and gaseous products by withdrawing portions of the gases from the top and from the combustion zone of the furnace.

8. In the manufacture of ferro-phosphorus in a blast furnace, the process which consists in charging the furnace with a suitable mixture of phosphatic material, iron bearing material, fluxing material and carbon, igniting the charge at the base thereof, and supplying air into the combustion zone, and Withdrawing a portion of the gases from the combustion 4zone to control the reduction and combining action, whereby to obtain a slag product which is soluble in hydrochloric acid.

' 9. In the manufacture of ferro-phosphorus in a blast furnace, the process which consists in charging the furnace with a suitable mixture of phosphatic material, iron bearing material, iuxing material, and carbon, igniting vthe charge at the base thereof, and supplying air into the combustion zone, and withdraw-- ing a portion of the ases existing in the combustion zone of the urnace to cause the production of a slag product which is soluble in hydrochloric acid; and then collecting and drawing off said slag product.

10. In the manufacture of ferro-phosphorus in a blast furnace, the process which consists in charging the furnace with a suitable mixture' of phosphatic material, iron bearing material, fluxing material, and'carbon, igniting the charge at the base thereof, and supplying air into the combustion zone, and withdrawing al portion of the gases from ren the combustion zone, to control the reducing and combining actions carried on in the furnace and to produce a slag product which is soluble in hydrochloric acid, and finally drawing of the slag product while in molten condition.

1l. In the manufacture of ferro-phosphorus in a blast furnace, the process which consists in charging the furnace with phosphatic material, iron bearing material, fluxing material, and carbon, igniting the charge at the base thereof and supplying air into the combustion zone, withdrawing a portion of the gases from the combustion zone, and finally recovering from the withdrawn gases the Valuable constituents thereof.

12. In the manufacture of ferro-phosphorus in a blast furnace, the process which consists in charging the furnace with phosphatic material, iron bearing material, uxing material, and carbon, igniting the charge at the base thereof and supplying air into the combustion zone, withdrawing a portion of the gases from the combustion zone, subjecting the gases to the action of water, precipitating solid portions from said gases to form a sludge, and treating the sludge to recover elemental phosphorus therefrom.

13. In the manufacture of ferro-phosphorus in a blast furnace, the process which consists in charging the furnace with phosphatic material, iron bearing material, iuxing material, and carbon, igniting the charge at the base thereof and supplyingI air into the combustion zone, withdrawing a portion of the gases from the combustion zone, sub jectingthe gases to the action of water, precipitating solid portions from said ases to form a sludge, and distilling the slu ge and recovering elemental phosphorus from the distillate.

14. In the manufacture of ferro-phosphorus in a blast furnace, the process which consists in charging the furnace with phosphatic material, iron bearing material, fluxing material, and carbon, igniting the charge 4 at the base thereof and supplying air into the combustion zone, witlgrawing the gases from the top of the furnace and precipitating from such withdrawn gases the silica, alumina,

lime and other solid substances to form aU cleaning and polishing material.

In testimony whereof I have hereunto set I my hand on this 18th day of March, A. D.

JOHN WILLIAM WALTON. 

